User`s manual for cycle programming

CENTERING (Cycle 240) 3.2
3
HEIDENHAIN | TNC 640 | User’s manual for cycle programming | 9/2015
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3.2 CENTERING (Cycle 240, DIN/ISO:
G240)
Cycle run
1 The TNC positions the tool in the tool axis at rapid traverse
FMAX to set-up clearance above the workpiece surface.
2
The tool is centered at the programmed feed rate F to the
programmed centering diameter or centering depth.
3 If defined, the tool remains at the centering depth.
4 Finally, the tool path is retraced to setup clearance or—if
programmed—to the 2nd setup clearance at rapid traverse
FMAX.
Please note while programming:
Program a positioning block for the starting point
(hole center) in the working plane with radius
compensation R0.
The algebraic sign for the cycle parameter Q344
(diameter) or Q201 (depth) determines the working
direction. If you program the diameter or depth = 0,
the cycle will not be executed.
Danger of collision!
Use the machine parameter displayDepthErr to
define whether, if a positive depth is entered, the
TNC should output an error message (on) or not (off).
Keep in mind that the TNC reverses the calculation
for pre-positioning when a positive diameter or
depth is entered. This means that the tool moves
at rapid traverse in the tool axis to set-up clearance
below the workpiece surface!